Thomas, Ewan; Ficarra, Salvatore; Nunes, João Pedro; Paoli, Antonio; Bellafiore, Marianna; Palma, Antonio; Bianco, Antonino

Journal of Strength and Conditioning Research 37(5):p 1145-1156, May 2023. | DOI: 10.1519/JSC.0000000000004400

PURPOSE:

To review articles that performed stretch (flexibility) training and its effect on muscular strength.

PROCEDURES:

A literature search was performed using three databases. Studies were included if they compared the effects on strength following stretch training vs. a non-training control group or stretch training combined with resistance training (RT) vs. an RT-only group, for least four weeks of intervention.

A total of 35 studies (n = 1,179 subjects) were included in this review, and the interventions lasted for a mean period of 8 weeks (range, 4–24 weeks), 3–4 days per week, applying approximately four sets of stretching of approximately 1-minute duration.

CONCLUSIONS:

The stretching vs. non-training control group showed a significant small effect on improving dynamic but not isometric strength following static stretching programs.

Stretching added to RT indicated no significant effect; however, moderator analysis showed that stretching before RT sessions had a small but negative effect but a significant negative association with the longer the study.

Chronic static stretching programs increase dynamic muscular strength to a small magnitude.

Performing stretching before RT for a prolonged time (>8 weeks) can temper strength gains to a small-to-moderate magnitude.

Performing stretching removed from RT sessions might be a strategy to improve strength development.

IN PLAIN ENGLISH:

Muscle stretching/flexibility exercises have a place in one’s training program. For the most part, when performed regularly it has some benefits relative to dynamic muscle function. However, if the goal is to improve muscular strength only, it is best to complete it post-workout as pre-workout stretching may attenuate strength.